Failsafe system for copying machine

ABSTRACT

A failsafe system is provided for a copying machine which will operate in response to one of a plurality of sensing devices to stop the xerographic copying process, immediately deenergize the fuser assembly and energize an auxiliary drive system which will merely return the reciprocatable document carriage to the home position so that the original document may be retrieved. When the document carriage reaches the home position, the auxiliary drive system will be shut off with the cover latching mechanism deactivated to prevent the initiation of further cycles until such time as repairs are made and the system is reset for normal operation.

United States Patent Inventors Appl. No.

Filed Patented Assignee Richard E. Hosey Ironton, Ohio; Thomas A. Hoskins; Myron F. Shlatz;

James W. Stanley, all of Lexington, Ky.

Apr. 10, 1969 June 22, 1971 International Bus'ness Machines Corporation Armonk, NY.

FAILSAFE SYSTEM FOR COPYING MACHINE 11 Claims, 12 Drawing Figs.

Int. Cl ..G03g 15/00, G03b 27/62 Field ofSearch ..355/3,8, 14

[56] References Cited UNITED STATES PATENTS 3,471,230 10/1969 Koslo et al.

Primary Examiner-Samuel S. Matthews Assistant Examiner-Kenneth C. Hutchison An0rneySughrue, Rothwell, Mion, Zinn and Macpeak ABSTRACT: A failsafe system is provided for a copying machine which will operate in response to one of a plurality of sensing devices to stop the xerographic copying process, immediately deenergize the fuser assembly and energize an auxiliary drive system which will merely return the reciprocatable I document carriage to the home position so that the original document may be retrieved. When the document carriage reaches the home position, the auxiliary drive system will be shut ofi' with the cover latching mechanism deactivated to prevent the initiation of further cycles until such time as repairs are made and the system is reset for normal operation.

Pmmwmwn 8,586,450

SHEET 1 OF 6 ATTORN S PATENIED mm m SHEET 2 [1F 6 moi/E PATENIEU JUH22 I971 SHEET 5 UF 6 F|G.9 I

FAILSAF E SYSTEM FOR COPYING MACHINE BACKGROUND OF THE INVENTION A 1. Field of the Invention The present invention relates to a failsafe system for a xerographic machine which will automatically shut down the operation of the machine when the failsafe circuit is activated as a result of improper operation of the machine as indicated by a plurality of sensing devices of when the failsafe circuit is manually activated.

More specifically, the present invention provides a system for retrieving the original document should the xerographic copying process be shut down before completion of a copying cycle, and also provides for safety interlocks to prevent the initiation of new copying cycles until the situation which caused the machine to go into failsafe" is remedied.

2. Prior Art In numerous prior art xerographic copying machines, a plurality of sensors have been provided at predetermined points along the path which the copying paper traverses during the usual xerographic copy cycle. If these sensors are not operated by the arrival of the copy paper at a predetermined point of time in the copying cycle, the sensors will provide a signal which will cause the machine to go into failsafe" and shut down the operation of the entire machine. This basic type of failsafe system has numerous modifications and the immediate shut down of the entire system ordinarily did not pose a serious problem with respect to retrieving the original document being copied since the document was usually held in a stationary position over a fixed transparent window in a readily accessible location.

However, in certain prior art xerographic machines, the document to be copied is placed on a movable carriage and reciprocated with respect to a scanning optical system. In this type of machine, the document carriage usually enters into an enclosed portion of the xerographic copying machine and if the entire system were to be shut down immediately upon detection of an unsafe or improper condition while the document was within the machine, it would be impossible to retrieve the original document until such time as a serviceman would arrive to open up the machine.

The present invention provides a failsafe system which will shut down the main xerographic copying process immediately upon detection of an unsafe or improper condition in the machine but overcomes the problem of documental retrieval providing an auxiliary drive system for merely returning the document carriage to the home position so that the original document may be removed from the machine SUMMARY OF THE INVENTION In a xerographic copying machine of the type having a movable document carriage which is guided for reciprocating movement past an optical scanning device and a drive mechanism for reciprocating the carriage in timed relation with respect to the rotation of the xerographic drum, an auxiliary drive system is provided comprising an auxiliary motor, a timing having interconnecting sprocket means on the shaft of said motor and on the shaft of main drive system, tooth means connected to the sprocket means on the shaft of the main drive system rotation therewith, lever means operatively positioned with respect to said tooth means sought upon energization of said auxiliary motor said tooth means will rotate through a single cycle and engage said lever means intermediate the ends of said cycle to return said carriage to said home position.

A plurality of paper sensing switches are located along the path of the copying paper and upon failure of the copy in to actuate said switches within a predetermined time said switches will provide a signal which will shut down the main drive system and the fusing assembly and energize the auxiliary driving system to return the document carriage to the home position. A torque switch in the main drive system, a paper discharge kicker activated switch and a manually operable stop switch are also provided to accomplished the same end.

BRIEF DESCRIPTION OF THE DRAWINGS coupling system for operatively connecting either main xerographic drum drive system or the failsafe drive system to the reciprocatable copy carriage;

FIG. 5 is an end elevation view of the drive coupling arrangement for connecting the failsafe drive to the reciprocatable copy carriage drive when operating in the failsafe mode;

fig. 6 is a side elevation view of the cover latching arrangement with the cover in unlatched condition;

FIG. 6a is a detailed elevation view along the line 6-6 of FIG. 6;

FIG. 7 is a view similar to FIG. 6 showing the cover in latched condition;

FIG. 7a is a detailed elevation view along the line 7-7 of FIG. 7;

FIG. 8 is a side elevation view of the solenoids for controlling the over latching arrangement when operating in the failsafe mode;

FIG. 9 is a side elevation view of the cover latch control linkage for automatically unlatching the cover at the end of a failsafe operation and FIG. 9a is an exploded view of the individual levers shown in FIG. 9 indicating the relative pivotal arrangement of the levers.

DETAILED DESCRIPTION OF THE INVENTION The xerographic copying'machine involved in the present application is similar in operation to the xerographic copying machine disclosed and described in detail in copending application Ser. No. 778,492 filed Nov. 25,l968,entitled Drive Coupling System" and assigned to the assignee of the present invention.

The general arrangement of the various elements which make up a copying machine is shown in FIG. 1. In copying machines of this type a sheet of copy to be reproduced is scanned the image is directed onto a rotating drum having a photosensitive surface thereon. The drum 10 shown in FIG. I is provided with a renewable photoconductive surfaces 14 which is disposed on a film 18 which may be stored on rolls 11 and 15 within the hollow drum 10. After a predetennined number of copies have been made, the rolls 11 and 15 may be suitable indexed whereby a new length of film 18 is disposed about the surface of the drum 10 thereby providing a new photosensitive surface 14 on the drum. A sheet of copy 12 to be reproduced is placed face down upon a traveling copy bed 13 which may be reciprocated in a manner more fully described in the copending application. The portion of the copy bed 13 upon which the copy 12 is placed is transparent so that light from light sources 17 will illuminate the copy as the copy bed 13 is reciprocated past the opening between the two light sources 17. The light reflected from the sheet of copy to be reproduced is directed downwardly and focused on thesurface of the rotating drum 10 by means of the lens 16. A uniform charge is placed on the surface 14 of the film 18 by means of the main corona discharge-unit 20. The charge on those portions of the surface 14 which receive the light will be dissipated thereby leaving a negative image of the copy to be reproduced on the surface 14. The surface of the drum then passes in close proximity to a cascade developer unit 22 wherein a plurality of carrier particles having positively charged toner adhered to the surface thereof are cascaded over the surface 14. The positively charged toner particles are then adhered to the negatively charged image on the surface 14.

A roll of paper 24is dispensed by means of a suitable paper feed unit and the endless sheet paper coming from the roll 24 is cut into suitable lengths by means of cutters 26. The individual sheets of paper are then passed by a suitable conveying means into intimate contact with the surface of the drum in registration with the image formed thereon. The negatively charged transfer corona unit 28 transfers the positively charged toner particles from the image of the surface of the drum to the sheet of paper at this point. The sheet of paper adhering to the surface of the drum is then stripped from the drum by any convenient means, not shown. The positively charged preclean corona unit 32 is disposed adjacent the surface of the drum to facilitate the removal of any remaining toner particles by means of the rotating brush 34. A suitable vacuum source is provided which draws the toner particles which are removed from the surface of the drum by the brush 34 into the disposable bag 36 and the surface of the drum is now ready to receive another negative charge from the main corona discharge unit 20. The sheet of paper having the toner particles thereon is then conveyed by suitable means to a fuser assembly 38 whereby the toner particles are permanently fixed to the paper. The paper is then conveyed to a suitable discharge rack 40.

A plurality of paper sensing switches are located along the path of the paper as it proceeds from the roll of paper 24 to the discharge rack 40. A first paper sensing switch S1 is related immediately after the cutters 26, a paper sensing switch S2 is located adjacent the point where the sheet of paper leaves the drum, a paper sensing switch S3 is located immediately after the fuser assembly 38 and a kicker activated switch S4 is provided in the discharge rack 40. Should the paper fail to arrive at any of the paper sensing switches at a predetermined point of time in the cycle of operation, the switches will be actuated to close a circuit and send the machine into the failsafe operating mode. Paper sensing switch S3 is, in effect, two switches and not only senses the leading edge of the paper but also programmed to sense the trailing edge of the paper. This is to insure that the paper sheet has completely passed from beneath the fuser assembly. As stated previously, paper sensing switch S3 is located immediately after the fuser assembly 38 and this location is immediately adjacent the entrance to the discharged rack 40. Once the paper has passed paper sensing switch S3, the paper will be entirely within the discharge rack adjacent the wall switch S4 thereon. Since the paper is conveyed through the fuser assembly and into the discharge rack by an endless perforated conveyor belt having a vacuum plenum chamber located therein, not shown, to hold the sheet of paper on the belt, it is necessary to provide a kicker arm 42 in the discharge rack toseparate the sheet of paper from the belt and transfer the sheet to the opposite side of the rack for stacking. The operation of the kicker arm is initiated by paper sensing switch S3 as it senses the trailing edge of the paper. It is essential that the kicker return to its initial position ready for the sheet of paper or else the next sheet of paper will become jammed with ,a portion thereof extending into the fuser assembly 38 thereby creating a fire hazard. Therefore, a kicker return actuated switch S4 is provided. If the kicker arm is not returned to the proper position at a predetermined point of time in the cycle of operation, a signal will be provided to place the machine in the failsafe mode.

A timing wheel, not shown, is placed in the drive train of the machine having degree markings located about the circumference thereof and a suitable zero position indicator is provided adjacent the wheel so that the service man can tell, by merely looking at the position in which the timing wheel has stopped relative to the indicator, which of the switches S1 S2, S3,, S3 or S4 has caused the machine to go into the failsafe mode. The following chart shows the approximate relationship of the failsafe switches to the cycle of operation as shown on the timing wheel: 1

If the switch S1 was actuated, this would provide an indication that the paper is exhausted on the supply roll 24 or jammed at the cutters 26 and the operation of the machine would be shut down until such time as a new supply ofpaper is placed on the machine or the jam is cleared and the machine is reset for a new cycle of operation. If the switch S0 is actuated, this would initiate that the sheet of copy paper was not removed from the surface of the drum l0. Actuation of this switch will shut down the operation of the machine until such time as the machine can be opened and the improperly adhered sheet of copy paper removed from the surface of the drum. The switch S3 is most important from a fire safety point of view since this particular switch is located immediately after the fusing assembly and if actuated would provide an indication that the sheet of copy paper has become jammed in the fusing assembly. lf such a condition exists, the intensive heat from the fusing assembly could easily start a fire in the machine and actuation of the switch S3, either leading or trailing, will shut down the operation of the machine and disconnect the heating elements of the fuser assembly 38. Once again, it will be necessary for. the machine to be opened, the errant piece of paper removed and the machine reset for a new cycle of operation. The kicker actuated switch S4 in the discharge rack 40 is actuated if the kicker arm fails to return after stripping a sheet of copy paper from the conveyor belt at the correct point of the cycle. A manual power off switch on the top of the machine, not shown, and a torque responsive switch adjacent the main drive train, not shown, are also provided. Both of these switches, if actuated, will also result in placing the machine in the failsafe mode.

In each of these instances the operation of one of the abovementioned switches could occur at any point in the copying cycle of the xerographic machine. Since the present type of machine utilizes a reciprocating document carriage, it then .follows that the document carriage could be located at any point in its reciprocating cycle. If the document carriage is located within the machine, that is, not at the document loading station, it would ordinarily be impossible to retrieve the original document from the carriage until such time that the service man would be obtained. In order to provide for the retrieval of the original document when the machine is shut down due to the operation of one of the above-mentioned switches an auxiliary drive system has been provided which will operate solely to return the carriage to the home position.

As described in detail in the above-identified copending application, a drive coupling system is provided for reciprocating the document carriage in timed synchronization with the rotation of the xerographic drum. Referring now to FIGS. 4 and 5 of the present application, a drive disc 72 is provided which corresponds to the drive disc 72 in the copending application. A main driving pawl 82 and a backcheck pawl 92 are pivoted on gear plate 78 and are adapted to be pivoted into driving engagement with driving teeth 74 and 76, respectively, on the drive disc 72. During the normal copy cycle the pawis 82 and 92 will be engaged in driving relationship with the teeth 74 and 76 on the drive disc 72. A first lever 60 is pivoted on bracket 61 which is secured for rotation with the detent plate 122 and is provided with three arms 62, 64 and 66. The arm 66 is provided with a slot 68 which receives an adjustable stud 80 which is utilized to perform a camming function with respect to another lever 95. A spring 81 is connected at one end to the stud 80 and at the other end to backcheck pawl mounting pin 94 on gear plate 78 to normally bias the lever 60 into a position which is clockwise to the position shown in FIG. 5 with the flange 104 resting against a portion of the bracket 61. Adjacent the detent plate 122 a sprocket gear 85 is journalcd on the shaft 52 upon which the drive disc 72 is secured. Secured to the sprocket 85 for rotation therewith is an auxiliary driving member 88 having a single tooth 90 projecting from the circumference thereof. The tooth 90 is provided with a radially disposed drive face 91 and a sloping rear face 93. During a normal cycle of operation the arm 62 of the lever 60 will be biased out of the path of the tooth 90. A second lever 95 is pivoted on the same pin 84 upon which backcheck pawl 92 is mounted on the gear plate 78 and is provided with an arm having a projection 94 therein which overlies the backcheck pawl 92. The other arm of the lever 95 is disposed in contact with the cam stud 80 which is secured to the am 66 of lever 60. A third lever 96 is provided on the same stud 84 as the main drive pawl 82 is provided with two arms 98 and 100. The arm 100 is provided with a bent end portion 102 which is adapted to bear against a flange 104 on the arm 64 of lever 60. A spring 105 connected to arm 100 and an ear 101 n on the mounting bracket 61 secured to the detent spring 105 normally biases the lever 96 such that the end 102 will be disposed in interfering relation with the flange 104 when arm 62 of lever 60 is being driven by tooth 90 during "failsafe." I

The arm 98 of the lever bear against a roller 106 mounted on a lever 108 which is pivoted in the frame of the machine and normally biased by spring 107 in a direction to dispose the roller 106 in the path of the lever arm 98. When the lever 60 is not being driven by the tooth 90 of the failsafe drive system and the arm 98 of the lever 96 comes in contact with the roller 106 on lever 108 during a normal copying cycle, since spring 107 is stronger than the spring 105 the lever 96 will yield and the end portion 102 of arm 100 of lever 96 will be moved out of interengagement with flange 104 on lever 60. When the end portion 102 and flange 104 are in abutting engagement during failsafe, the interference friction between 102 and an 104 will prevent the lever 98 from yielding to the lever 108 until the end of the lever 108 bears against abutment 103. At this time the lever 96 will yield and the engagement between flanges 102 and 104 will be broken.

An auxiliary drive motor 110 is mounted by suitable bracket means on the frame of the machine with the shaft 112 thereof disposed parallel motor the shaft 52 upon which drive disc 72 is secured. A sprocket gear 114 is secured to the shaft 112 and an endless sprocket chain 116 is trained about sprocket gears 114 and 84 to impart rotation from the motor 110 to the tooth 90 secured to sprocket gear 84.

The operation of the failsafe coupling arrangement shown in F 168. 4 and 5 may be summarized as follows. During a normal cycle of operation, the drive shaft 52 will be driven by the man driving motor to rotate the xerographic drum. The pawls 82 and 92 will be engaged with the during surfaces 74 and 76, respectively, on the driving disc 72 which is secured for rotation with the shaft 52. The drive disc 72 rotates in the direction of the arrow as shown in FIG. 4 and drives the sheave 51 in the same direction in the manner described in the above-identified, copending application. The rotation of the sheave 51 in this direction will move the reciprocating copy carriage in the scanning direction, that is, toward the home position at the load unload station.

Upon activation of any one of the above-mentioned switches which are capable of initiating the failsafe mode of operation, the copy bed will be decoupled from driving relation with the copy drum and the failsafe motor 130, FIG. 2, will be energized to drive the sprocket 132 in the direction of the arrow thereon to rotate the sprocket 85 in the direction of the arrow thereon through the sprocket chain 134. A cam disc 136 is mounted for rotation with the sprocket 132 and is provided with a cam 138 adapted to control the switch arm 140 of the stop switch 142. During normal operation of the machine the cam 138 will be disposed slightly to the left of the position shown in FIG. 2 and the roller 144 on the end of the switch arm 140 will be disposed in contact with the periphery of the cam disc 136. With the switch arm 140 in this position, the switch 142 will be closed to precondition, the failsafe motor 130 for operation upon closure of one of the above-mentioned failsafe switches.

The sprocket 85, upon energization of the failsafe motor 130, will rotate in the same direction as the sheave 51 during the scanning portion of the copying cycle. Upon closure of one of the failsafe activating switches the main motor will be shut off, thereby stopping the rotating of the shaft 52 and the drive disc 72 mounted thereon. Since the sheave 51 will already have rotated through a portion of the scanning stroke, the gear disc 78 and the detent plate 122 will also have rotated through the same portion of the scanning stroke and the arm 62 or the lever 60 will be disposed at a point on he circumference of the auxiliary driving member 88 a predetermined number of degrees away from the tooth 90 on the driving member 88. Simultaneously, with the energization of the failsafe operating switch the heating elements of the fuser as sembly 38 will be ,shut off as well as the power to the various corona discharge devices and the cascade developing apparatus 22. The power to the vacuum source for the paper conveying belt will be maintainedduring the failsafe mode of operation to hold the paper away from the hot portions of the fuser assembly.

As the tooth 90 begins to rotate it will catch up with the arm 62 of the lever 60 and upon contacting the arm 62 will pivot I the lever 60 such that the pin 80 mounted on the lever engages and pivots lever clockwise. The projection 94 engages and rotates the backcheck pawl 92 outof engagement with driving tooth 76 so that the xerographic drum is effectively decoupled from the copy bed and the copy bed can be driven home by the failsafe motor 130. counterclockwise movement of lever 60 also causes flange 104 on its arm 64 to bear against the end 102 of the arm of lever 96. The geometry of the flange 104 and the end portion 102 is such that the rotation of the lever 96 about its pivot point is prevented and since the lever 60 cannot rotate further in the counterclockwise direction as viewed in FIG. 5, the lever 60 will provide rigid driving link between the tooth 90 and the lever 96 which is mounted on the gear plate 78. Thus, as the-tooth 90 completes its singles cycle of revolution, the gear plate 78 and the sheave 51 which is coupled thereto will rotate to complete the scanning stroke of the reciprocating carriage to the home position.

As the tooth 90 nears the near of its single cycle of revolution, the lever 98 of the lever 96 will be contacted by the roller 106 on the end of lever 108. The lever 108 will yield until it contacts the fixed abutment 103 at which time the roller will present a fixed resistance to the. lever 96 thereby causing the lever 96 to pivot in a counterclockwise direction as viewed in FIG. 5 thereby disengaging the end portion 102 from the flange 104 thereby allowing the lever 60 to pivot out of engagement with the tooth 90. At the instant the tooth 90 clears the arm 62 of lever 60 the spring 81 will return the lever 60 to its normal position for further failsafe operations. At the same instant the cam 138 will raise the switch arm 140 of the switch 142 upwardly to open the circuit to the failsafe motor 130. The end of the switch arm will be latched in the raised condition by the latch 146 which is pivoted to a bracket rigidly mounted in the machine. With the switch arm 140 in the raised position, the switch 142 will be held open, preventing energization of the failsafe motor until such time as the trouble is removed and the xerographic copy machine is reset for normal operation. After the earn 138 has raised the switch arm 140 into locked position and disconnected the current to the motor 130, the inertia will be sufficient to allow the cam 138 to travel just past the roller 144 so that upon unlatching of the latch member 146 the roller 144 will be allowed to drop onto the circumference of the cam disc 136, closing switch 142 to precondition the failsafe motor for future operation.

Switch 142 is also provided with additional contacts to disconnect the main power switch and the vacuum motor for the paper conveyor belt. Contacts may also be provided for closing a circuit to a signal light, indicating the need for a serviceman.

Atthis stage in the operation of the failsafe mode of operation, the copy carriage will be located at the home position and the cover will be unlatehed, allowing retrieval of the hereinafter, it is impossible to close and relatch the cover to initiate additional cycles until such time as the trouble is repaired and the machine is reset. The cover, not shown, is

provided with a latch 152, FIGS. 6 and 7, which must be latched by a complementary latching arrangement in the base of the machine before a copying cycle can be initiated. The complementary latching mechanism is comprised of a bracket 154 secured to the frame 156 of the cover. A bell crank lever 158 is pivoted at 160 to the bracket 154 and is normally biased into the position shown in FIG. 6 by the spring 162. A look arm 164 is rigidly secured to one arm of the lever 158 and is guided for vertical movement in a slot in the guide plate 166. The end 168 of the lock arm 164 is adapted to be engaged by the notch 170 in the lock lever 172 which is shown in another perspective in FIG. 9.

A latch lever 174 is pivoted at 176 to the lock arm 164 and the arm 178 thereon is disposed in engagement with the fixed stud 180 on the bracket 154. The lever 174 is normally biased in a counterclockwise direction as viewed in FIG. 6 by means of a spring 182 under the limiting control of the stud 180 on the arm 178 of lever 174.

After a document has been placed on the movable copycarriage, the cover is lowered, moving the latch 152 downwardly in the direction of the arrow in FIG. 6. The downward movement of the latch 152 will cause the-latch 152 to contact the flange 184 on the end of the bell crank lever 158 to pivot this lever in a clockwise direction about the pivot point 160. This pivotal movement of the lever 158 will cause the pivot point 176 to move in a downward direction about the pivot 160. By

varying the position-of the pivotpoint 176 with respect to the stud 180, the lever 174 will be biased by the spring 182 in a counterclockwise direction, bringing the complementary latching part 174 into interengaging locking relationship with the latch 152 as shown in FIG. 7.

Simultaneously, with the latching engagement between latch 152 and complementary latch lever 174, the locking arm portion 168 will be engaged by the notch 170 in lever 172. This additional interlocking allows lever 172 to be pivoted to initiate starting of the copying cycle as will be described in more detail hereinafter.

Turning now to the arrangement shown in FIG. 9, it is clearly shown that the lever 172 which cooperates with the lock arm 168, and the various levers associated with the lock lever 172, all operate in a plane perpendicular to the general plane of operation of the levers shown in FIG. 7. As a practical matter, the arrangement of FIG. 7 and the arrangement of FIG. 9 are located on-adjacent sides of the xerographic copying machine adjacent the top upper corner thereof immediately adjacent the home position of the reciprocating carriage. As

mentioned above, in order to maintain the latch lever 174 in interlocking engagement with the latch 152, it is necessary for the lever 168 to be captured in the notch 170 of lever 172. The lever 172 is pivoted at 186 to a bracket plate 188 which is mounted on-the optical frame 156' of the machine and is normally biased in a counterclockwise direction as viewed in FIG. 9 by the spring 190 connected between the frame156 and the arm 1920f the lever 172. Thus, when the lever 172 is biased into interlocking engagement with the lock arm portion 168, the end of lever 192 will simultaneously operate microswitches 194 and 196 by engagement with the plunger 198. These microswitches must be closed as a precondition to initiating a xerographic copying cycle by depression of a start button, not shown. At the completion of a normal copying cycle or multiple copying cycles, the connecting rod 200 which is connected to the lever 172 is actuated to pivot the lever 172 and release the lock portion 168 to unlatch the cover and allow removal of the document from the machine. The specific manner in which the connecting rod 200 is operated does not form a portion of the present invention and it is, therefore, not described in detail at this time.

However, when the machine enters into the failsafc mode of operation, the mechanism for controlling the connecting rod 200 is disabled and the following arrangement is provided to unlatch the cover upon return of the copy carriage to the home position and maintain the cover in the unlatched position until such time as the trouble has been corrected and the machine reset for normal operation. I

A carriage detecting lever 202 is pivoted at 204 to the bracket plate 188 and is adapted to be engaged by the copy carriage as it returns to the home position. A main control lever 206 is pivoted at 208 to the bracket plate 188 and is provided with a flange 210 at one end thereof disposed in engagement with one end of lever 202. An auxiliary control lever 212 I is pivoted at 214 to the opposite end of the main control lever 206. The auxiliary control lever 212 is biased in a counterclockwise direction as viewed in FIG. 9 by the spring 216 to a position such that the end 218 of the lever -212 will be disposed sufficiently remote from the end 220 of the lever arm 222 which is integral with the lock lever 172 for a reason to be set forth in greater detail hereinafter. The opposite end 224 of the lever 212 is disposed in engagement with a flange 226 formed on the end of lever 228 which is pivoted at 208 to the bracket plate 188. A latch lever 230 is pivoted at 232 to the main control lever 207 and is provided with a latching shoulder 234 adapted to cooperate with the flange 226 on the lever 228.

. FIG. 9a shows the main control lever 206, the auxiliary control lever 212, the lever 228 and the latch lever 130 in an exploded view. The dot-dashlines show the relationship of the pivot points of the various levers with respect to the main control lever and the dash lines show the bearing relationship between the various levers.

A pair of bowden cable clamps 236 and 238 are mounted on extensions of the main control lever 206 and secure the covers of bowden cables 240 and 242, respectively, to the main control lever 206. An eyelet member 244, secured to the end of bowden cable 240, is adjustably secured to the lever 228 by means of a clamping screw 246-and the eyelet member 248, secured to the end of bowden cable 242, is adjustably secured to the latch lever 230 byclamping screw 250.

When the machine is operating in the normal manner and the copy carriage returns to the home position, the copy carriage will contact the lever 202 and pivot the lever 202 in a counterclockwise direction about pivot point 204. Due to the interengagement between the lever 202 and the flange 210 on the lever 206, the lever 206 will be pivoted in a clockwise direction, as viewed in FIG. 9. With the end 218 of the lever 212 disposed in the position shown in FIG. 9, the end 218 will not contact the end 220 of lev'er arm 222 when the main control lever 206 is pivoted upon return of the copy carriage to the home position. Thus, the control of the lock lever 172 remains completely under the control of the push rod 200 with respect to unlatching the cover.

In FIG. 8 a failsafe solenoid 252 and a paper-out solenoid 254 are secured to a mounting plate 256 which is secured to the frame 156 of the machine. The armature 258 of the failsafe solenoid 252 is connected to one arm of a lever 260 which is pivoted to the mounting plate 256. The bowden cable 240 is secured to another arm of lever 260 which is provided with a switch operating end projection 262. A further arm of lever 260 is provided with a switch operating arm 264 so that upon energization of the failsafe solenoid 252 by any one of the failsafe initiating switches described previously, the lever 260 will be pivoted to actuate switches 266 and 268 as well as pull the bowden cable 240 to the left as viewed in FIG. 8. The operation of the switch 266'disconnects the main drive motor and the fuser lamp as well as the paper vacuum motor. However, actuation of the switch 268 will reconnect the circuit to the paper vacuum motor and failsafe motor 130 for the duration of the failsafe of operation.

The' paper-out solenoid 254 is adapted to be energized by the contacts of switch 270, shown in FIG. 2, which may be manually operated depressing the plunger 272 when it is desired to restore the machine to normal operation u-pon correction of the defect. A rigid arm 274 is secured to the plunger 272 and one end of a bowden cable 276 is secured thereto. The opposite end of the bowden cable 276 is secured to a flange 278 on the-switch latching lever 146. Energization of the solenoid 254 will draw the armature 280 upwardly to pivot the lever 282 in a counterclockwise direction as viewed in FIG. 8. One end of the bowden cable 242 is secured to the arm 284 of lever 282 and a further arm 286 of lever 282 is disposed in engagement with the switch operating lever for switch 288.

Thesequence of operation with respect to FIGS. 2, 8 and 9 can be briefly summarized in the following manner. At the beginning of a normal cycle of operation the cover of the machine will be lowered and a lock arm end portion 168 of the cover latching mechanism previously described above with respect to FIGS. 6 and 7, will be captured by the notch 170 in the lock lever 172 which is biased by the spring 190. As the lever 17 locks the lock arm end portion 168, the lever arm 192 will operate the plunger 198 to operate the microswitches 194 and 196. The copy carriage will then be quickly traversed from the home position to the start of scan position in the manner more fully described in the above-identified copending application, and begin the return scanning portion of the cycle. If, for any of the above-described reasons, the machine goes into failsafe mode of operation, the failsafe solenoid 252 will be energized to rotate the lever 260 which, in turn, will shift the bowden cable 240 within its housing and simultaneously operate switches 266 and 268 to energize the failsafe motor, deenergize the main drive motor and fuser assembly and transfer the power lead-in for the paper vacuum motor.

Energization of the failsafe motor 130 will return the copy carriage tothe home position'in the manner described above with respect to FIGS. 2, 4 and 5. As the failsafe motor returnsthe copy carriage to the home position, the carriage will engage the lever 202 in FIG. 9 to pivot lever 202 which, in turn, will pivot the lever 206. Due to the operation of the bowden cable 240 by means of the failsafe solenoid 252, the lever 228 will be pivoted counterclockwise as viewed in FIG. 9 and thereby pivot the auxiliary control lever 212 clockwise against the bias of the spring member 216. As the lever 228 rotates, the flanges 226 on the end thereof will be captured by the notch 234 in the latch lever 230 which is also biased by the same spring member 216. Thus, the lever 212 will be latched in a position whereby the end 218 thereof will contact the flange 220 on the end of lever 222 when the lever 206 is rotated by the return of the copy carriage to the home position. This engagement between lever 212 and lever 222 is sufficient to pivot lever 172 in the clockwise direction to unlatch the lock arm portion 168, thereby unlocking the cover. The lever 172 will be maintained in the unlatched positioned by the auxiliary controllever 212 so that even if the cover of the machine is closed it will be impossible to latch the cover to allow starting of the machine for a subsequent copy cycle.

When the trouble in the machine has been remedied and it is desired to reset the machine for normal operational cycles, the plunger 272 of the reset switch 270 may be actuated by the authorized service man. In order to prevent unauthorized operation of the switch 270, the switch 270 is generally mounted in an obscure location in the machine, such as behind a baffle plate which is only accessible by opening the paper supply drawer at the bottom of the machine. Thus, the switch 270 will be disposed out of sight so that unauthorized personnel would not generally be aware of the location of the switch.

Upon pressing the plunger 272 of the switch 270, the arm 274, rigid with the plunger 272, will pull the bowden cable 276 to pivot the switch latching lever 146 in a counterclockwise direction as viewed in FIG. 2 to release the switch actuating arm 140. This will allow the roller 144 to drop into contact with the circumference of the cam disc 136 thereby closing the switch contacts in switch 142 to predispose the failsafe motor for future operation.

Depression of the plunger 272 will also close the contact of switch 270 to, energize the solenoid 254 which will rotate the lever 282 in a counterclockwise direction as viewed in FIG. 8

to pull the bowden cable 240 and'operate the switch 288. By pulling on the bowden cable 242, the latch member 230 will be rotated in a counterclockwisedirection as viewed in FIG. 9 against the bias of spring 216 to unlatch the lever 228 which will then be returned to a position shown in FIG. 9 under the influence of the spring 216 on the lever 212. With the lever 212 returned to the position in FIG. 9, the spring may bias the lever 172 into locking engagement with the lock arm end portion 168 when the cover is lowered so that a new cycle of normal operation may be initiated. Simultaneously, the closure of the contacts of switch 288 will initiate the operation of the paper feed to remove any paper from the machine. Thus, with the cover latching mechanism cleared for normal operation, the copy carriage returned to the home position, the failsafe motor shut off and primed for future operation the power restored to the main drive motor and fuser assembly, and the machine cleared of all paper along the copying path, the machine is now ready for normal xerographic copying operations.

What we claimed is:

1. In a xerographic copying machine of the type having a rotatable xerographic drum and a reciprocable document carriage movable from a loading position to a remote position and adapted to be synchronously coupled to said drum for return movement to said loading position comprising, first drive means for rotating said xerographic drum, first coupling means for synchronously coupling said carriage to said first drive means during a normal copying cycle, second drive means adapted to be energized upon detection of an abnormality during the copying cycle, abnonnality detection means operable to deenergize said first drive means and energize said second drive'means, and second coupling means operable subsequent to energization of said second drive means for disconnecting said first coupling means and connecting said second drive meansto said carriage to return said carriage to said loading position.

2. In a xerographic copying machine as set forth in further comprising means defining a path of travel for copy paper, said abnormality detection means including at least one paper sensing switch means disposed along said path of travel to sense the movement of a copy paper through said machine.

3. In a xerographic copying machine as set forth in claim 1 wherein said second drive means is comprised of an electric motor, cam means rotatable by said motor, switch means for controlling said motor operable by said cam means to provide for a single revolution of said motor, said single revolution being sufficient to return said carriage to said loading position, and latch means for holding said switch means in the position of disconnecting said motor subsequent to actuation by said cam means.

4. In a xerographic copying machine as set forth in claim 1 wherein said first and second coupling means are mounted for rotation about a common axis, said second coupling means comprising a single tooth'means mounted for rotation adjacent said first coupling means and driven by said second drive means, first lever means pivotally mounted on said first coupling means with a portion thereof disposed in the path of rotation of said tooth means, second lever means pivotally mounted on said first coupling means and disposed in engagement with said first lever means for disconnecting said first coupling means upon pivotal movement of said first lever means by said tooth means.

5. In a xerographic copy machine as set forth in claim 4 further comprising third lever means pivotally mounted on said first coupling means andadapted to be positioned in interfering relation with the pivotal movement of said first lever means upon engagement of said tooth means with said portion of said first lever means to provide a drive from said tooth means to said carriage through said first lever means, said third lever means and the portion of said first coupling means connected for movement with said carriage.

6. In a xerographic copying machine as set forth in claim 5 further comprising cam means disposed adjacent the path of rotation of said third'lever means for disengaging said third lever means from said first lever means and interrupting the drive from said tooth means to said carriage upon the completion of a single revolution of said tooth means.

7. In a xerographic copying machine as set forth in claim 1 further comprising cover means located at said loading station, cover latching means for locking said cover in the closed position during a copying cycle and cover unlatching means normally disposed in an inoperative position during a normal copying cycle.

8. In a xerographic copying machine as set forth in claim 7 further comprising activating means operable by said abnormality detection means to shift said cover unlatching means from said inoperative position to an operative position.

9. ln a xerographic copying machine as set forth in claim 8 12 further comprising means adapted to be contacted by said carriage operatively connected to said cover unlatching means to unlatch said cover when said cover unlatching means is disposed in its operative position.

10. In a xerographic copying machine as set forth in claim 9 further comprising latch means for holding said cover unlatching means in the operative position for unlatching said cover and maintaining said cover in the unlatched position subsequent to the operation of said abnormality detection means.

11. In a xerographic copy machine as set forth in claim l0 further comprising reset means adapted to release said latching means to allow said cover unlatching means to move to the inoperative position. 

1. In a xerographic copying machine of the type having a rotatable xerographic drum and a reciprocable document carriage movable from a loading position to a remote position and adapted to be synchronously coupled to said drum for return movement to said loading position comprising, first drive means for rotating said xerographic drum, first coupling means for synchronously coupling said carriage to said first drive means during a normal copying cycle, second drive means adapted to be energized upon detection of an abnormality during the copying cycle, abnormality detection means operable to deenergize said first drive means and energize said second drive means, and second coupling means operable subsequent to energization of said second drive means for disconnecting said first coupling means and connecting said second drive means to said carriage to return said carriage to said loading position.
 2. In a xerographic copying machine as set forth in further comprising means defining a path of travel for copy paper, said abnormality detection means including at least one paper sensing switch means disposed along said path of travel to sense the movement of a copy paper through said machine.
 3. In a xerographic copying machine as set forth in claim 1 wherein said second drive means is comprised of an electric motor, cam means rotatable by said motor, switch means for controlling said motor operable by said cam means to provide for a single revolution of said motor, said single revolution being sufficient to return said carriage to said loading position, and latch means for holding said switch means in the position of disconnecting said motor subsequent to actuation by said cam means.
 4. In a xerographic copying machine as set forth in claim 1 wherein said first and second coupling means are mounted for rotation about a common axis, said second coupling means comprising a single tooth means mounted for rotation adjacent said first coupling means and driven by said second drive means, first lever means pivotally mounted on said first coupling means with a portion thereof disposed in the path of rotation of said tooth means, second lever means pivotally mounted on said first coupling means and disposed in engagement with said first lever means for disconnecting said first coupling means upon pivotal movement of said first lever means by said tooth means.
 5. In a xerographic copy machine as set forth in claim 4 further comprising third lever means pivotally mounted on said first coupling means and adapted to be positioned in interfering relation with the pivotal movement of said first lever means upon engagement of said tooth means with said portion of said first lever means to provide a drive from said tooth means to said carriage through said first lever means, said third lever means and the portion of said first coupling means connected for movement with said carriage.
 6. In a xerographic copying machine as set forth in claim 5 further comprising cam means disposed adjacent the path of rotation of said third lever means for disengaging said third lever means from said first lever means and interrupting the drive from said tooth means to said carriage upon the completion of a single revolution of said tooth means.
 7. In a xerographic copying machine as set forth in claim 1 further comprising cover means located at said loading station, cover latching means for locking said cover in the closed position during a copying cycle and cover unlatching means normally disposed in an inoperative position during a normal copying cycle.
 8. In a xerographic copying machine as set forth in claim 7 further comprising activating means operable by said abnormality detection means to shift said cover uNlatching means from said inoperative position to an operative position.
 9. In a xerographic copying machine as set forth in claim 8 further comprising means adapted to be contacted by said carriage operatively connected to said cover unlatching means to unlatch said cover when said cover unlatching means is disposed in its operative position.
 10. In a xerographic copying machine as set forth in claim 9 further comprising latch means for holding said cover unlatching means in the operative position for unlatching said cover and maintaining said cover in the unlatched position subsequent to the operation of said abnormality detection means.
 11. In a xerographic copy machine as set forth in claim 10 further comprising reset means adapted to release said latching means to allow said cover unlatching means to move to the inoperative position. 